The present invention relates to an improved fan exit guide vane installation system for use in gas turbines.
In a gas turbine engine used for propulsion, a fan case and a smaller diameter compressor case cooperate to radially bound an annular fan duct. Fan exit guide vanes span across the fan duct to de-swirl working medium fluid flowing therethrough. The outer and inner extremities of the vanes are connected to the fan and compressor cases respectively. Traditionally, the outer connection is effected by a pair of bolts. The inner connection, by contrast, includes numerous parts including spacers, nuts, bolts, and inserts.
This type of system presents problems from a replacement or maintenance standpoint. Occasionally, a vane will become damaged in use and need to be replaced. Using the connection system described above, replacement of a single damaged vane is difficult. In U.S. Pat. No. 5,690,469 to Deal et al., the issue of replacing a vane is addressed. In this patent, a repair kit for replacing an unserviceable vane assembly is described. The repair kit includes a serviceable vane subassembly having a serviceable airfoil with a base attached to the root end and an opposing base which is unattached to, but slidably engagable with the serviceable airfoil. The opposing base is slipped over the tip end of the airfoil and slid toward the base attached to the root end. The vane subassembly and opposing base are pivoted into position between inner and outer engine cases in place of an unserviceable vane assembly so that sockets in the attached base engage support pins extending from the inner case. An adhesive is applied to the tip end of the serviceable airfoil and the opposing base is translated into its installed position near the tip end of the serviceable airfoil. Upon curing of the adhesive, the opposing base becomes attached to the airfoil. The base is secured to the outer case by studs and nuts.
There is a need for a simpler system for installing fan exit guide vanes which reduces the quantity of parts, the cost of the parts, and the weight of the parts. There is also a need for a simpler system which facilities the repair of damaged vanes.
Accordingly, it is an object of the present invention to provide an improved system for installing a vane such as a fan exit guide vane to a support structure in a gas turbine.
It is a further object of the present invention to provide a system as above which has a reduced quantity of connection parts and reduced weight.
It is a yet another object of the present invention to provide an economically beneficial installation system.
The foregoing objects are attained by the system of the present invention.
In accordance with the present invention, a system for installing a vane broadly comprises a structure for supporting an inner end of a vane, a receptor pocket in the support structure, and a boot attached to a first or inner end of the vane for insertion into the receptor pocket. In a first embodiment of the present invention, the receptor pocket is machined into the support structure and is preferably open-ended and curved in configuration. The boot is preferably formed from a resilient dampening material, such as silicone rubber, and has a depth greater than the depth of the receptor pocket in the support structure.
In an alternative embodiment of the system of the present invention, an opening is machined into the support structure and an insert is placed into the opening to act as the receptor pocket. To install a vane, the boot on the vane is placed in the insert. The insert is provided with a flange portion which rests on a peripheral ledge machined in the support structure. The peripheral ledge maintains an upper surface of the flange portion substantially flush with an upper surface of the support structure. Retention devices may be used to hold the insert within the opening.
Other details of the installation system of the present invention, as well as other objects and advantages attendant thereto, are set forth in the following detailed description and the accompanying drawings in which like reference numerals depict like elements.